This invention relates in general to a tamper detection system. More specifically, this invention relates to a system to detect tampering with a water supply valve.
In many locations, water is supplied to residential, commercial, and industrial properties from a source such as a water treatment plant. The water source is typically operated by a public utility company that provides water to customers for a fee. The water is commonly distributed from the source throughout an area such as a municipality using a network of water mains.
A supply line may be connected to one of the water mains in order to provide water to a property. A flow meter is typically included on the supply line so that the amount of water flow to the property may be measured. This allows the property to be billed for the water used. A stop valve is also typically included on the supply line so that the water flow through the supply line may be stopped. The water flow may be stopped when the property is unoccupied, or when the owner of the property is delinquent in paying a bill for the supplied water.
The stop valve is typically located in a convenient position to allow an employee of the public utility company to stop the water supply to the property. At a residential property, the stop valve is often included in a curb box assembly. The curb box assembly includes an underground box that contains the stop valve. The underground box may be several feet below the ground surface. A conduit connected to the box extends to the ground surface to provide access to the box. The conduit is typically four to six inches in diameter, and four to five feet long. The conduit is typically capped with a bolted-on lid. The employee may remove the lid from the conduit and use a tool, commonly referred to as a curb key, to manually open and close the stop valve.
In some situations, the public utility company will stop the water supply to a property but the owner or a tenant of the property will open the stop valve in order to turn the water supply to the property back on.
To help prevent this from happening, public utility companies have attempted various procedures to deter or prevent someone from unauthorized access to the stop valve. A plug may be inserted in the conduit which rests on top of the stop valve and helps block access to the stop valve. One known type of plug is a simple wooden dowel having a metal weighted end. Due to the narrowness of the conduit relative to its length, it is difficult to remove the plug from the bottom of the conduit. Although the plug helps deter water theft by blocking access to the stop valve, determined individuals have been known to remove the plug and operate the stop valve without the permission of the public utility company. The public utility companies often do not have the resources to monitor and determine when the stop valve has been tampered with until a meter reading indicates that the water is being supplied to the property. It is relatively expensive for the public utility companies to send personnel at random intervals to monitor tampering of the stop valves. It is desirable to have an improved system to indentify when a stop valve has been improperly tampered with.